1. Field of the Invention
The present invention relates to a radiation detection apparatus, a manufacturing method thereof, and a radiation detection system.
2. Description of the Related Art
In recent years, digital radiation detection apparatuses, in which a scintillator that converts radiation into light of a wavelength that can be detected by a photoelectric conversion element is laminated on a sensor panel on which a plurality of photoelectric conversion elements are formed, have been commercialized. Scintillators consisting of Tb-doped GdOS or an alkali halide material such as Tl-doped CsI are predominant. When a vacuum deposition method is performed using an alkali halide scintillator material, a scintillator layer that includes a set of columnar crystals is formed. However, as shown in FIGS. 3A and 3B, because a scintillator layer 500a has gaps 502 between columnar crystals 501a, some of the radiation incident on the scintillator layer passes through these gaps 502, and reaches the sensor panel without being converted into light. Because the sensor panel is not able to detect radiation that has not been converted into light, the detective quantum efficiency (DQE) of the radiation detection apparatus decreases.
In order to increase the amount of light emitted by the scintillator layer, Japanese Patent Laid-Open No. 2008-051793 proposes a radiation detection apparatus in which a plurality of scintillator layers having different concentration distributions of Tl are formed on a sensor panel. In order to suppress the growth of abnormal growth portions such as splashes, Japanese Patent Laid-Open No. 2005-148060 proposes a technique for forming a plurality of scintillator layers over a plurality of iterations.